Deletion of a Node from Doubly Linked List

This article is part of article series - "Datastructures".

Previous Article: Inserting a Node in Doubly Linked List.

Deletion of a Node 

Let us say our current Doubly Linked List is as shown in Figure-1.

Figure 1: Current Doubly Linked List

• Deleting First Node of the List
Now we have to delete First Node from the List shown in Figure-1. Because of this operation HEAD and Node-2 are affected.

In HEAD - FIRST variable should now point to NODE-2 (i.e HEAD->FIRST = HEAD->FIRST->NEXT). If you see HEAD->FIRST->NEXT actually HEAD->FIRST currently points to NODE-1 so HEAD->FIRST->NEXT is equivalent to NODE-1->NEXT which is NODE-2.

In NODE-2 - NEXT variable remains unchanged and PREV variable should now point to NULL since it is the first Node in the List.

Decrement LENGTH variable in HEAD so that it maintains proper count of Nodes in the List.

Pseudocode:

HEAD->FIRST = HEAD->FIRST->NEXT

NODE-2->PREV = NULL

decrement(HEAD->LENGTH)

Output:

Figure 2: After deleting the First Node in the List.